ERC FUNDED PROJECTS

The Virtual Element Method (VEM) is a novel technology for the discretization of partial differential equations (PDEs), that shares the same variational background as the Finite Element Method. First but not only, the VEM responds to the strongly increasing interest in using general polyhedral and polygonal meshes in the approximation of PDEs without the limit of using tetrahedral or hexahedral grids. By avoiding the explicit integration of the shape functions that span the discrete space and introducing an innovative construction of the stiffness matrixes, the VEM acquires very interesting properties and advantages with respect to more standard Galerkin methods, yet still keeping the same coding complexity. For instance, the VEM easily allows for polygonal/polyhedral meshes (even non-conforming) with non-convex elements and possibly with curved faces; it allows for discrete spaces of arbitrary C^k regularity on unstructured meshes. The main scope of the project is to address the recent theoretical challenges posed by VEM and to assess whether this promising technology can achieve a breakthrough in applications. First, the theoretical and computational foundations of VEM will be made stronger. A deeper theoretical insight, supported by a wider numerical experience on benchmark problems, will be developed to gain a better understanding of the method's potentials and set the foundations for more applicative purposes. Second, we will focus our attention on two tough and up-to-date problems of practical interest: large deformation elasticity (where VEM can yield a dramatically more efficient handling of material inclusions, meshing of the domain and grid adaptivity, plus a much stronger robustness with respect to large grid distortions) and the cardiac bidomain model (where VEM can lead to a more accurate domain approximation through MRI data, a flexible refinement/de-refinement procedure along the propagation front, to an exact satisfaction of conservation laws).

980 634 €

Start date: 2016-07-01, End date: 2021-06-30

Friction and wear are liable for enormous losses in terms of energy and resources in modern society. Costs related to unwanted friction in industrialised countries are estimated to be about 3% of the gross domestic product. Urgency is even greater nowadays as friction between micro-components has become the bottleneck of several applications for which miniaturisation is critical. Lubrication is a commonly adopted solution to reduce friction. Graphite is a broadly used solid lubricant for large scale applications, while the lubricating properties of a few-layers graphene hold great promise especially for smaller scale applications. At present, our knowledge of the friction and lubrication of rough surfaces is essentially phenomenological. This is because friction is only deceivingly a simple mechanisms, which instead requires understanding of physical phenomena simultaneously acting at different length scales. The change in contact size, which controls the friction stress, depends on nano-scale phenomena such as atomic de-adhesion, sliding, dislocation nucleation in metals, but also on micro- and macro-scale phenomena as (size-dependent) plastic deformation. The objective of this proposal is to reach an unprecedented understanding of metal friction and lubrication by accounting, for the first time, for all relevant phenomena occurring from the atomic to the macro-scale, and their interplay. To this end, a seamless concurrent multi-scale model will be developed. The power of this new model lies in its capability of describing three-dimensional bodies with realistic roughness in sliding lubricated contact, with the accuracy of an atomistic simulation. This research builds towards a complete picture of metal friction and lubrication. The materials chosen for the proposed research are copper and multi-layer graphene. However, the model that will be developed is general and can be used to study different materials, lubricants and environmental conditions.

1 999 985 €

Start date: 2016-06-01, End date: 2022-11-30

Recent discoveries clearly show that non-retroviral RNA viruses, despite not coding for reverse transcriptase and integrase, can transfer genetic material to their hosts, similarly to DNA viruses and retroviruses. The distribution of non-retroviral integrated RNA viruses (NIRVs) in host populations, mechanisms of NIRVs formation and effects on hosts are unclear. The main objective of this proposal is to uncover the complex biological interactions between non-retroviral RNA viruses and their hosts using the model system “Aedes albopictus and Flavivirus”. This system is ideal because Ae. albopictus is a known vector of non-retroviral RNA viruses, including several highly relevant for public health such as dengue viruses (Flaviviridae, Flavivirus) and NIRVs phylogenetically related to Flaviviruses have been identified in its genome. First, a population genomic approach will be used to interrogate the genome of Ae. albopictus from different geographic populations at their DNA and RNA levels. This approach will permit the systematic characterization of the distributions of NIRVs in natural host populations, the analyses of correlations between the presence of NIRVs and viral infections and the description of NIRVs genomic context, from which insights on mechanisms of NIRVs formation can be derived. Secondly, tissue-specificity of the NIRVs, their trans-generational stability and impact on mosquito biology will be analysed in a controlled laboratory environment. Somatic integrations could contribute to acquired immunity to their respective viruses or establishment of persistent viral infection. Germ-line integrations could have an evolutionary impact. If NIRVs affect Ae. albopictus vector competence or the genome of emerging viral populations, they could be manipulated for vector control purposes. Additionally, results on NIRV distribution in natural host populations and mechanisms of NIRVs formation will have implications in medicine because several non-retroviral RNA viruses are emerging as delivery systems for gene therapy applications.

1 686 875 €

Start date: 2016-05-01, End date: 2022-04-30

"Ultra-short light pulses with large instantaneous intensities can probe light-matter interaction phenomena, capture snapshots of molecular dynamics and drive high-speed communications. In a semiconductor laser, mode-locking is the primary way to generate ultrafast signals. Despite the intriguing perspectives, operation at Terahertz (THz) frequencies is facing fundamental limitations: engineering ""ultrafast"" THz semiconductor lasers from scratch or finding an integrated technology to shorten THz light pulses are currently two demanding routes. SPRINT aims to innovatively combine the groundbreaking quantum cascade laser (QCL) technology with graphene, to develop a new generation of passive mode-locked THz photonic laser resonators, combined with unexplored electronic nanodetectors for ultrafast THz sensing and imaging. To achieve these ambitious objectives, the versatile quantum design of QCLs will be exploited to engineer the laser gain spectrum on purpose. Resonators of unusual symmetry and shape, like photonic quasi-crystals or random patterns, will be implemented, offering the flexibility to control and guide photons and the lithographic capability to embed miniaturized intra-cavity passive components to probe and modulate light. Graphene, owing to its gapless nature and ultrafast, gating-tunable carrier dynamic, will lead to a major breakthrough: integration in the THz QCL cavity will allow superbly manipulating its functionalities. Antenna-coupled quantum-dot nanowires will be also devised to sense and probe ultra-short THz pulses. The project will target radically new concepts and interdisciplinary approaches encompassing unconventional THz QCL micro-resonators, graphene and polaritonic THz saturable absorbers, non-linear ultra-low dimensional detection architectures. Pushing forward the understanding of ultrafast dynamics in complex THz electronic and photonic systems, SPRINT prospects new directions and long-term impacts on fundamental and applied science."

1 990 011 €

Start date: 2016-09-01, End date: 2022-08-31